Indttctldn heateb fob and method of heating tibe holds



E. F. NORTHRUP INDUCTION HEATER FOR AND METHOD OF HEATING TIRE MOLDS Filed Nov. 20, 1920 4 Sheets-Sheet 1 Dec. 22 1925. 1,566,500

5. F. NORTHRUP INDUCTION HEATER FOR AND METHOD OF HEATING TIRE MOLDS Filed Nov. 20, 1920 4 Sheets-Sheet 2 QlA/W N IF Jrwerdvrr Dec. 22, 1925- .E. F.v NQRT-HRUP INDUCTION HEATER FOR ANDYMETHOD 0F HEATING TIRE MOLDS Filed Nov. 20, 1920 4 Sheets-Sheet a Dec. 22 1925. 1,566,500

E.. F. NORTHRUP INDUCTION HEATER FOR AND METHOD OF HEATING TIRE MOLDS Filed NOV. 20, 1920 I 4 Sheets-Sheet 4 7910. lf'yjl.

Passe-a Dec. 22, 1925.

UNITED STATES "PATENT OFFEE.

FITCH NORTHBUP, OF PRIHOETON', NEW JERSEY, ASSIGNOR T0 AJA X ELEGTBO- trauma conrom'rron; JERSEY,

""mnucrroz; nearer. roam unrnon or trauma To all whom/it may concern:

Be it known that I, Enwm F. Nonrnnur; a citizen of the United States, residing at 30 Wiggins St, Princeton, in the county of I Mercer and State of New Jersey, have invented a. certain new and useful Induction Heater for, and Method of Heating Tire Molds, of whichthe following is a specifica- Another purpose is to heat electricallyconducting annular articles' including in'ner tire molds in position within'the tires, by

electrical induction from a high frequency current. The article heated may thus be the ultimate article .manufactured or may be a tool orapparatus for treating the ultimate article. 7 v

' A further purpose is to apply induction i from high frequency electric. current to annular articles typified by tires and tire molds while they and the coils through which the indu'ctionis applied are moved relatively with respect to eachbther-preferably while I the tires'or molds. and tires are passing to the point of intended encasement the" outer. molds. r

A further purpose is to "mount coils through whichf'alternating electric current is to be passed upon opposite sides of a path or track along which the annular artlcles such as tires, or inner molds and their tires are carried from the loading-point to a-point where they are delivered'. at the (intended .5 temperature, regulating the t'empergture by regulation of the speed of transfer, the current supplied or any'other means.

A further purpose is to apply miilti-phase' OK TBENTOQH, FEW JEBSEY A CORPORATION (1)1 NEW rmn moans.

' Application filed November 20, 1920. Serial No. 425,439.

current through water,cooledooils in inductive relation to a tire or rubber covered mold,

preferably applying or releasing the water at the neutral point of the multi-phase sys-i A further purpose is to induce current by ahigh frequency coilwhose turns are in line axially-with an annulus to be heated and the mean diameter of whose turns is determined 'by the" mean diameter of that Egrtion of the annulus to which the heat is to I particularly applied. The cylindrical zone of induction set u may thus be given maximum effect or desirable uniformity of heating may be secured.

Further purposes will appear in the specification and in the claims. a

My invention relates to the methods involved as well as to mechanism by which the method may be carried-out. p

Inthe drawings I have preferred to illustrate several variations of one general form only among the many in which "it may be carried out, se'lectin a form which is. practical, eflicient, relia 1e and economical of space and current. and which at the same time well illustrates the principles of my invention. Y

Figure 1 is aside elevation of a mechanical structure illustrating my invention.

Figure 2 is a horizontal section of a struc-' ture corresponding to Figure 1 with diagrammatic connections.-

Figure 3 is a perspective view of part of the mechanism shown in Figures 1 and. 2-,

ing mechanism and showing water connections.

Figure 4 is a side elevation of a tire moldwhich is to be heated.

. Figure 5, is a sectional perspective pt the I same ring.

- Figure 6,is ahorizontal section with ,dia-

grammatic connections showing the heating coilsimilarto those of'1-3 with diagrammaticsin'gle phase multiple connections con-' denser and discharge gap.

omitting the tires and molds, and supportv 95 figure-7 is 'a view corresponding part with Figure 6 but showing single phase generator current supply in multiple.

Figure 8 is an enlarged sectionalview of a single pair of coils with a mold and tire and with diagrammatic single phase current supply. 1

res

9, 10 and 11 are side elevations of 001 8 illustrating different proportions of the coils with respect to the molds heated to 10 secure difierentheating efiects.

Figures 12 and 13 are side and end elevationsrespectively of an outer mold which may be heated by my method and apparatus.

- Figure 14 is a top plan view of apparatus 15 for heating both outer and inner tire molds. Figure 15 is a side elevation of a coil applied to a locomotive tire.

Figure 16 is a side elevation of horizontal coils and track for heating locomotive tires. 2 Figures 17 and 18 are longitudinal and transverse sections, respectively, of a construction for heating rods in which the effect of successive coils is integrated. The" figure is partly diagrammatic. c 2 An excellent illustration of the advantage of integrating the heating effect of successive coils occurs in the heating of the molds during the making of the outer shoes of pneumatic tires. L v

In the vulcanizing of tires it is customary to place the tires upon a metal internal mold 15 such. as isshown in Figure 4, surround them by -an external mold 16 such as is shown in Figures 12 and 13 and then heat the combined mass within an oven by superheated steam until vulcanization has taken lace. As the internal mold receives its heat exclusively by conduction from the outer mold it heats slowly from the outer mold with the result that the outer part of the tire is heated to a vulcanizing temperaturelong before the inner mold' is raised to any such temperature and the outer part ofthe tire is given excessive treatment relative to the interior thereof. This difierence in the treatment aflects the quality of the tire.

' In addition a relatively excessive time is taken for the operation.

My invention is designed to overcome this objection by initial heating of the inner mold preferably to-or above a .vulcanlzmg temperature with the tire in place upon the moldbefore the tire and inner mold are placed I heat' of the outer mold may take place either y my method or by any other without necessity for also heating the inner mold through the outer mold. This secures a .-much.closer approach to uniformity in tem- 3 perature .and length of-timeof treatment of all parts of the tires than-by the existing methods,

It is my purpose to apply electrical mduction to the annulus, whatever it be, here the tire mold through approximating in "sidered as typical of any carrier system.

-my bread invention. The effect will be betwithin the outer mold, so that quick 'and' support the combined. mold and tire in a vertical lane by any convenient means such as a rame 18 and rods 19, extending upwardly to the carriers 20. The carriers are shown as resting through rollers 21 upon a track 22, the whole mechanism being con- So that I may move the different elements of the carrier system forward as desired to carry the molds and tires edgewise, I connect the carriers at 23, forming a system by which the several tires 17 and their inner molds may be moved forward regularly,'if desired, or by intermittent action to hold them in position forelectrical heating treatment as preferred.

The mechanism. of Figures 1 to 3 with its staggered coils on oppositesides of the tires is designed for continuous progress of the tires and molds from a loading point to a point of delivery at which they are to beenclosed within the outer tire molds. Whether thisprogress be continuous orintermittent therewill be successive additions of heating effect from the successive coils, which effects. will be summed up orintegrated in the mold as finally heated, carrying out one form of 5 10 ter in a 'magnetizable article than in one which is merely electrically conductive, both because of the relatively high resistance of ironqmd steel and because of the hysteresis present there. 1

In the form shown in Figures 1 to 3, I have applied three phase high frequency current obtained from any three phase low frequency star supply 24, 25 and 26 charging condensers 27 and discharging through gaps 28. The high frequency current thus obtained is applied to the molds through coils which arehere shown as arranged 1n staggered groupsof four coils each, two on one side of the path] and two on the other, the series being repeated if desired to form as many coils as needed. "The coils for one phase are shown at 29 and 30 on' the far side of thepath and at 31 and 32 upon the near side. The coils of the next phase are shown at 33 and 34 on the far side and at 35 and 36 uponthe near. side, and thecoils of the third phase are shown at 37 ,38 upon the far side and at 39 and 40 upon the near side. 7

Thou h this is a convenient form of plac- 1,5ee,uoo

ing the coils and extends the group to a phase supply, providing a considerable travel of the tires and molds, it will be evident-that many other forms may be used, with feweror more coils per phase, with a difl'er'ent number of bases, single,- two phase or greater, and with successive groups of coils or sets of coils in series or in parallel' to cover the desired extent of tire mold travel, as the wish of the designer orthe needs of the particular installation may dictate. The tires may also be carried to their positions to receive the induction, .heated' either all at one time or in several different positions between several stages of move ment and then hemoved to place for. insertion within the outer molds.

In the-form shown in the figures the coils are made of pipes so as to form a water cooling'system, the water being shown as drawn through a grounded pipe 41 representing the neutral point of the/ star system and being discharged at 42, 43, 44 at or near the points of application of several phases of current. controlled by'valve 41. It has been my experience that the conductivity of ordinary faucet water to high frequency. current is so low that a few feet of clear discharge or of flow through an insulating pipe is sufficient so that no'substantial leakage will take place.

" The connections from the condensers to the conductor pipes are made by wires 45,

46 and 47. Following out the connections from terminal 42, the current passes to coil 32, through this coil and thence to and through coils 31, 29, and 30 respectively to neutral connection 48. The current from terminal 43 passes through the pipe forming coils 36, 35 33 and 34 respectively to neutral, and the current from terminal 44 passes through coils 40, 39, 37 and 38. All of these .coils' are so arranged as to give nearly opposite coils the same direction of induction and to form as little conflict between the inductions set up in adjoining'coils as pos- -taining uniform sible, with the effect and result that the inner mold-passing through between the coils will be continuously subjected to induction having a high heating effect. With iron both hysteresis "and eddy currents will be I set up within the metal ofthe molds. 55

Water cooling ofthe coils prevents them from becoming heated, avoiding the injurious effect which excessive heating of the coils/would have upon the rubber and mainthe coils. v

.The staggering of the coils gives a more nearly uniform heating action than would otherwise bethe case, though the overlappingof difler'ent parallel coils by each of themolds'as it passes also tends toequalize The flow of water is electrical conditions within.

upon the carriers for movement 'alongthc track. When the ,current is turned on, the initial tires and molds are started at one end of the apparatus, say at the left end, and are fed toward the right end preferably at a regularspeed determined upon in proportion to the temperature to which the molds areto be raised and the time in which this is to be accomplished at the selected rate of current input. The movement-may, how ever, be intermittentwith one stage or many stages. As the molds leave the coils, in the preferred operation they are delivered in regular succession for encasement in outer molds such as are shown in Figures 12 and 13. Except in Figure 14, I have not shown these outermolds as heated by my method for the reason merely that the greater bulk and easier accessibility ofthese outer molds makes it possible to heat them' readily by separately or together by any method and applied hot upon opposite sides of the tire;

1n which event the halves of the pair forming a complete outer mold may be heated separately as in Figure 14 or together by my method, by passing them along'upon a track through and between coils of the same characterand available in the. same-variety as the coils and' currents for heating the innehmolds. The outer mold may also be heated by my method after the inner mold and tire have been placed within it. question of whether my method be used for this purpose or not is one of economy chiefly.

The inner molds are also separable, as is usual in this art, and as shown in Figure 4, but this separability does not affect the heat treatment appreciably except that, with high frequency current, the joints heat less than the metal between the joints. I In order to illustrate thefacts, that it is The not necessary to have multi-phase current, since single phase current may be furnished through condensers and discharge gaps to separate coils or pairs or sets of coils, in cluding asingle pair or to any number of sets in parallel; and that the same flexibility extends in regard to generator current with p out discharge gap, I have illustrated several of these variations in Figures 6, 7 and 8. o

In Figure 6 I have shown pairs of co1ls "52, 53; 54,55, and 56, 57 in parallel, the.

discharge gaps 63.

coils of each pair being placed directly opposite each 'other, and connected as at 58,

which may be used separately for heating individual molds or may be part of a system such as seen in Figure 8. The inlet 59 and discharge 60 are seen in the enlarged for any required time to bring it or them to the desired temperature While'the mold and coils are relatively immovable.

In the discharge gap I get'the best results with an enclosed gap having a double spacing from mercury to secure the advantage of thehigh negative electrode resistance to break off the spark abruptly. Such a' gap is shown in my copending application for filed June 18, 19 17.

patent for discharge ap, Ser. No. 175,518, owever,"I show it and the transformer conventionally with a view =to. covering any gap. and any source of current which may be used.

In Figure 7 a generator is used at 64 with a condenser 62'thrown across its terminals, capable of supplying coils in series or in multiple or in combination of these connections, as with the other forms. Coils which ,are adjacent along the path .of mold travel 7 are here shown as'slightly overlapping.

All of thejconstructions shown may be used to heat molds which are moved at in tervals and which are stopped between movements so as to receive a maximum of induction; so that a part of the" advantage of my process-may be secured without continuity of movement. and in -fact without any movement during the time of heating. In Figures 9, 10 and 11- the coils 64, 65, 6t are shown as of dlflfering average diameters vin order to concentrate the current induced therefrom in different annular zones (radlally of the molds) to secure the results desired. Thus the means diameter of the coil 64 corresponds with the diameter of the-- outer part of the. mold 15 with the result. that the outer circumference will be heated first and the inner part of the mold will be heated chiefly by conduction therefrom.

The coil 65,'on-tl .l0tl1er hand has itsmean diameter agreeing substantially with the means diameter of the mold with the result that the mold will be heated nearly uniformly, the central section of the moldbeing heated first and. greatest'ahd the heat extending by conduction to the inner and outer perimeters.

In"the case of coil 66, the meandiameterr of the coil corresponds with'thediameter of an inner "part of the mold withthe result that the inner flanges of the mold will be heated'to the greatest extent and the heat will extend by conduction outwardly to the rest of the mold.

It will thus be seen that by varying the mean diameter of the coil or the area which the coil covers, as by coils of the character indicated, or combinations of coils, the mduction may be concentrated ticular width of belt or 'zone mold to givethe tire additional heat treatment or to heat it initially or most wherever desired.

The showing in Figures 12 and 13, already described, is, of course, the same whether the inner mold and tire be included or not.

In Figure 14 I show mechanism. for heating and delivering both inner molds with tires upon them' and outer molds ready for assemblage about the inner molds and tires Suitable supporting and conveying mechanism (not shown) advances one set of outer mold halves along a pathway 67, the inner 131F011 any PEI- molds "with their tires along a pathway 68-- and the other set of half outer molds along a pathway 69, the outer half molds having.-

esired in the theirconcavities towards each other ready.

for inclosure'of the inner moldsandtires. Coils 37 and 38 upon one side of the inner molds and tiresand 39 and 40-,upon; other,.may be part of an extensive system of heating'coils.

The outermold halves and m shown as acted upon by coils 37', .38 39:, 40 and 37, 38- 40 respectively (the 0011 corresponding the to 39' not being shown).

Each of these ets of coils may also be part of an extensive system; and the-same. capability exists of operating the system oi Figure 14 cotinuously or step by step or by soakin then a vancihg them to the-point of delivery, as in the case of all of n y other strucs tures.

- In any event the parts heated may be de livered in positions 72, 7 3,74 ready for .1l1- closure of the heated inner molds withtlres upon them within heated outer mold halves,

for subsequent heat, maintenance. by my. mold or by ovens or any other means to complete the vulcanization.

In Figure 15 a locomotive. tire 75 is shown as another good example of an annular member to be heated-as preliminary v to shrinkage upon-the wheel-and-as another;

good example of a structure in which the heating efiects of successive coils may be summed up or integrated. in aco'inmon article which is passed from one to the otherto receive their successive heating efl'ects viewed as difierentials. And this view of integrating is applicable'whether thedifferentials be small or great 'and whether" j they overlap because of uniform movement 1' the annular members treated and. v

of the article-or coils time separately applied with intermediate step y vances. An individual coil for such a tire is shown at 76.

Figure 16 is intended to illustrate not only the application of heat to locomotive tires 75 through coils 34, 37, 38 on one side and 36, 39 and 40 on the other, but also to 'gration of heatingeflects and of indicate that the character of the track or other device, or of the carrier usedto progress the articles and coils relatively, does upon horizontal platforms 77 preferably of I insulated material, forming floors of trucks supported by feet-78 and wheels 79 from any suitable horizontal track '80.. Any connecting mechanism and means of securing movement may be used or the device may be moved by hand. This is true also of the form shownin Figure 1.

In Fi ures .17 and 18 I have shown my method of integrating the heating effects of successive coils through which high frequency current is passed, in the heating of a bar or rod which is advanced or progressed, either continuously or intermittently as preferred, as by sets of rollers 81 and 82, suitably mounted, and one of them driven by any suitable gearing here ty ed by gears 83 and 84, of which 83is on the same shaft as the feed roller '82. {The coils 85, 86, 87, 88 and 89'are h shown as helical coils nearly fitting the bar, wire, rod

or strip 90. I have not considered it neces-.

, sary to illustrate the protecting covers for preventing undue cooling of the bar, etc. between the coilsas this could exist in great variety Obviously the'coils could be water cooled if desired, as in the annular coils shown. The coils could be one long coil if the rate of speed of the article permit this.

Such a mechanism as described is suitable, for example, for heating a bar, rod or wire from ;which nails or spikes are to be made; and one portion 91 of the bar or rod 'is separated as would be the case in the making of spikes. a

.Both hysteresis and eddy currents would be present and the bar, rod or wire would be delivered continuously or intermittently to the cutting or gripping mechanism of the nail. ,orspike machine at any temperature designed as required for the "heading and pointing operations.

It will be evident that my method'and mechanism" are c apable of usegenerally to heat or heat treat electrically conducting objectsin "motion or which are moved step bystep between the treatments, whether etizable or not; that the treatstep ad-- electrically conducting objects inwhich the heat is developed.

.molds continuously step the coils to these forms; and that the mate' rials primarily to be treated, when not electrically conducting, may be treated by mounting them on or encasing them within It will be further evident that the'appli-' cation of my process and. the character of apparatus may both be greatly varied, in the light of the disclosure herein, suiting t0 the needs of individual installations or'tlie; preferences of the designers." And I desire to include herein all such forms and varia 1 tions which come within the reasonable spirit and scope of my invention;

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is i 1. The method of integratingsuccessive heating effects from spaced electrical heating devices upon successive molds to be-he'ated which consists in moving the heating devices and the. molds to be heated with respect to each other, so as to bring the molds successively within the-electromagnetic field of each of said spaced devices- 2. The method ,of electrical heating electrically conductive molds by high frequency. current which consists in setting. up a plurality of fields of induction by passing high spaced one from another to set up separate fields'and in passing the molds to be heated from a position within the inductive-influ ence of one field to positions within the inductive influence of successive fields to integrate the successive heating effects of the separate fields.

'3. The method of inductively heating electrically conductive molds by high frequeneiy y a current which consists in progressive vancing the molds through spaced fields protive fields produced by high frequency elec- 1 tric current, summing up the eddy current heating effects of successive fields upon the molds and increasing its temperature as it 1s advanced. v ELThemet-hod of heating electricall concurrent which consists in advancing the y ste spaced j inductive fields produceif frequency-electric current, summing up the eddy current heating effects .of each'field upon the molds and increasing their temperatures as they are advanced. I

' 6. The method of heating an electrically conductive mold 'and delivering it hot at the ductive -molds by high frequency e ectric through by high frequency current through coil-like paths quency electric poiht of use which consists ill feeding the mold ro essively throu h a succession o spaced id fie s offorce pr need by high frecurrent and timing the rate of regression, the electrical input of each fiel and the 11 her of fields to deliver the mold at the requlred temperature.

7. The method of heating a paramagnetic moldb electric current which consists in advancln the mold through a plurality of spaced fie ds induced "by hi h frequency electric current to heat the "mo (1 by the summation of the hysteresis and eddy current heating effects from the successive fields.

' 8. Themethod of heating annular molds which consists in subjecting them to axiallyextending, cylindrical zones of electro-magnetic force and at the same time moving them transversely to their axes and the axes of the cylinders. 9. The method of heating tire molds, which consists in moving the molds in the planes of their'radii while inducing electric current across them.

10. The method of heating the molds, which consists in moving the articles in the planes of their radii through a field .of high frequency inductive force. e 1-1. The method of heating tire molds, which co'nsistsin moving the articles in the direction of the planes of their radii through a plurality of adj acent high frequencyv electric fields.

12. The method of heating tire molds, which consists in moving the articles in the direction of the planes of their radii through a luralit of adjacent, high frequency, overlapping e ectric fields.

13.- The method of heating tire molds, which consists in setting up a plurality of closely adjacent electric fields each corresponding approximately to their size and in moving the articles slowly through the fields edgewise. 14. The method of heating tire molds,

which consists in arranging coils for inductransferring them throu h the field.

tive' transfer of electric energy in closely adjacent pairs upon opposite sides ofa path, and in supporting the molds in the path. and wise from pair to pair to receive the in uctive efiects of the airs.

15; The method of heating tire molds, which consists in passing currents of electricity about circular paths having diameters ap roximately (H181 to the diameters of the mo ds and locate on opposite sides of them, while the molds are moved slowly 16. e method "of li ating tire molds, which consists in passing in h'frequency electric current through circu ar paths in adjacent pairs, the airs beingseparated arid the diameters of t e circular paths correspondin approximately to the diameters of f the mol s and in moving them edgewise from the field roduced by one pair through'the field r uced by the next adjacent pair to heat he molds. k v

17. The method of heating tire molds, which consists in passing high frequency electric current through opposite sets of circular-paths, the paths on opposite sides being separated and the diameters ofthe circular I paths corresponding approximately to the diameter of the tires or molds and paths on opposite sides overlapping, and in movin the molds edgewise from the field produce by one set through the field produced by the next adjacent set to heat the molds.

18. The method of heating tire molds,

which consists in utilizing the separate phases of a multi-phase high frequency electric current to set up pairs 'ofcircular paths of current flow, the paths from one phase adjoining those of the next phase and moving the fnolds edgewise through the space between the paths of the pairs to receive induction successively from the different phases. i

19. The method of heating tire molds,

which consists in J utilizing the separate tric current to set up. circular paths of current flow on" opposite sides of a space through which the molds ma be moved, the pat s from one phase adjoining those of the next phase and moving the molds edgewise through the space between the paths to receivelnduction successively from the different phases, and cooling the conductors h h cooling liquid.

21. The method of heating metal tire molds, which consists in moving the molds which the current is' passed by a I upon which the. tires are mounted edgewise throu h a passage ,while they are subjected to hig frequency electric induction.

22. The'method of heating metal tire molds, which consists in passing the molds with the tire mounted upon them edg wise through a passage while they are sub ected .to high frequency electric induction from ;c urrent"traveling in circular paths at the side of the passage of diameter approximating the diameter of the molds.

' 23. In the vulcanization of rubber tires -the method which consists in mounting the inner tire mold with the tire upon it while -molds which consists inpassing high freof a passage way and a source bf multitires upon their molds and exposing the the mold through the passage transversely molds with their tires upon them to high to the non-registering fields of force set up frequency electrical induction at the same thereby. H Y time that the mold is transferred across the 32. A source of high frequency electric field induced. V 7 current, coils fed thereby setting up spaced I.

24. In the vulcanization of rubber tires, fields of force and means for progressing a the method which consists in supporting a mold to be heated through the fields of force, tire shoe upon an inner annular metal mold so as to bringit successively within the fields and moving the mold edgewise with the tire of different coils. upon it through a plurality of high fre- 33. In apparatus for heating electrically U quency annular fields of force. conductive tire molds,'a pair of annular 25. In the vulcanization of rubber tires, coils approximately opposite each other, and the method which consists in supporting a a source of high frequency electric current tire shoe upon an inner annular metal mold, connected to the coils to give cooperative producing ,a lurality of overlapping annumagneto-motive force across the space from U lar fields of ectro-magnetic force and mov-v both coils, and a carrier for supporting theing the mold edgewise with the tire upon it mold to be heated between the coils. through the fields of force. 34. In apparatus for heating electrically. 26. In the vulcanization of rubber tires, conductive tire molds, .a pair of annular the method which consists in mounting a tire coils approximately opposite each other, and U shoe upon an inner mold, moving the mold a source of high frequency electric current edgewise and heating the mold while it is connected to the coils to give cooperative being moved edgewise, and in subsequently magnetomotiveforce across the space from surrounding the tire mold by an outer mold both coils, and a carrier for supporting the and concluding the vulcanization by heating mold to be heated between the coils and movthe outer tire mold. a ing it transversely to the axes of the coils. v 27.. In the vulcanization of rubber tires, 35.'In mechanism for heating electrically the method which consists in mounting a conductive tire molds, a pair of electrically tire shoe upon an inner mold, moving the connected coils placed on opposite sides of mold edgewise and heating the mold while it a space within which the articles may be is being moved edgewise, heating the outer placed, and having their axes out of line, to tire mold, appl ing the heated outer'mold cause the 'fieldsofthe coils to overlap withto the innermoi d and tire and subsequently out registration, in combination with a completing the vulcanization by maintain- S ur f h gh f equency C ent for the two ing the heat of the parts. coils.

28. Inthe vulcanization of rubber tires, 36. In'mecham'sm for heating electrically the method which consists. inheating the conductive tire molds, a pair of electrically inner tire ld. ith th tir i o iti conductive coils placed-on opposite sides of uponit, in separately heating the outer tire a p ce Within Which the mold m y be mold, in applying the heated outer tire mold p a d having their. axes out'of line, to to the tire and inner mold and in continuing cause. the fields 0f the coils to overlap i 1 to apply'heat to the outer tiremold during 0111? registration, in combination With 3' the co'mpletionof the vulcanization. ource of high frequency current for .the 29. In the vulcanization of rubber tires, tWO Coils n a upport for the 'mold to bev the method which consists in heating the h a d- 37 In mechanism forheating electrically the parts are. stationary and in subsequently nd v t r m ld a p r f electrically moving the tire and mold to a point where conductive coils placed on opposite sides of they are to receive the outer tire mold for a Sp hin which h mold m y b v the completion of the vulcanization; P and h v g their 3X68 t f line 150 30. In the vulcanization of rubber tires, cause the fields of the coils to overlap withthe method which consists in intermittently 011i registration, in combination h a moving the inner tire mold and tire 'u on it, of g f equency current for the two stopping the movement to apply elbctro- QIIS, a support for the mold-to 'be heated magnetlc induction for the heating of the Wlthill' 12 a C rrier f r m vin mold and delivering the tire and mold when the 3111101118 i 1ghjlhh space. heated for application ofthe outer tire mold A multirphasaheting System for iec? and completlon of vulcanization. v trically conducting tire molds, comprising a 31. .The method of electrically heating tire pl rali y of il alranged on opposite sides quencyelectric current throughsuccessive phase high frequency current therefor, setannular paths extending along the length of Aaing' up the inductance from different phases the passage on one side thereof and throu h in coils adjacent longitudinally of the passoverlapping non-re 'stering annular pat s age, and a carrier adapted to move the upon the opposite si e thereof and in moving molds to heated longitudinally of the f i passage, successively throu h the fields set up by different phases of t e current.

39. In mechanism for heating electrically conductive tire molds by high frequency coils, the coils having a mean diameter ap current, a pluralit of annular coils, having their planes para elfa source of high frequency current for the coilsand a carrier adapted to move the molds to be heated across the axes of the coils from one coil to I another.

40. In mechanism for heating electrically conductive tire molds by high freqiiency cur rent, a plurality of coils on one side of the passage way, a plurality of coils on the op-, posite side thereof, spaced so as to provide induction transversely "of the passage waiy the passageway, a pluralit of coils on theopposite side thereof, space so as to provide induction, transverselypf the passage way over a path longer than the greatest dimension of the coils, a high frequency source of electrical supply for thecoils-and a carrier forJfeedin-g the molds into thepassage and moving them longitudinally thereof while they are being acted upon by the in c 10 42. In mec anism for eating annular electrically conductive tire m ds plurality of annular coils arranged on opposite sides of a passage .way andcovering a greater length of passage way than the width of the coils, the coils having a mean diameter approximating that of the molds and a high frequency source of current for the coils.

43. In mechanism for heating'electrically conductive annular tire molds, a plurality of annular coils arranged on opposite sides of a passage way and covering a greater length of passage way than the width of the,

proximating that of the molds, a high frequency source of current for the coils and a carrier adapted to supportthe molds and move them into the passage way.

44. .In amechanism for electrically heating articles, a multi-phasesource of high frequency electric current supply, a plurality of coils arran edon opposite sides of a passage and ad acent lengthwise thereof, alternating coils having different phases and the coils being hollow, -and a source of liquid coolingsupply for the coils connecting at a neutral point with respect to the phases.

45. In an apparatus "for heating electrically conductive tirev molds by high frequem.

cy current, three sets of coils having a comphase star-wound electric sup 'ly therefor having the common connection oi ned to the mon connection, in combination witha threeasv neutral point of the star and having the windings connected at-their' opposite ends to the oints of the star through condensers and disc arge gaps.

46. In mechanism for heating electrically conductive tire molds by highfrequency,;a

inulti-phase electric current and a plurality of sets of coils arranged lengthwise along a passage and corresponding in number of sets to the phases of the current, in combination with a source! of multi-phase" alternating electrical current, having a neutral point and connections of said current to the-coils corresponding to the several phases, including condensers and discharge gaps.

EDWINIIFITCH noR'rHR' P. 

